With the development and further expansion of electric power grids and the increasing desire to locate portions of the electric cable system underground, demand for power cables used under medium voltage (i.e., in the range of about 6 to about 24 kV) is rapidly increasing. At the same time, the demand for power cable accessories associated with medium voltage power cables is accordingly also increasing.
A detachable T-shaped cable connector assembly (hereinafter simply referred to as T-shaped cable connector assembly) is one such power cable accessory. A T-shaped cable connector assembly includes a T-shaped connector sheath. The T-shaped connector sheath generally comprises: a T-shaped main insulation bushing; an inner semi-conductive shield layer disposed in the T-shaped main insulation bushing and integrally formed with the T-shaped main insulation bushing; and an outer, semi-conductive shield layer disposed on an outer surface of the T-shaped main insulation bushing and integrally formed with the T-shaped main insulation bushing. To control the electric field distribution at the shield end of the cable, an adapter in which an electric stress control layer is imbedded needs to be connected during usage of the cable connector. The manufacturing process of the connector sheath with the adapter is complicated and has a high cost. Moreover, a unique type of connector sheath has to be used with the cable to correspond to a particular cable cross section. The connector sheath therefore has generally poor versatility, and it can be difficult to mount the cable.
For example, a European Patent Application Publication No. EP911936(A1) discloses a T-shaped cable connector assembly. According to the publication, a stress control cone is imbedded in the main insulation bushing of the T-shaped connector sheath for controlling the electric field distribution at the shielding end of the cable. The connector sheath must correspond, or match, the cable cross section. The versatility of the connector sheath is poor, and the cable is difficult to mount in the connector sheath.
In U.S. Patent Application Publication No. US20050227522(A1), a T-shaped “cold-shrink” cable connector assembly is disclosed. The publication employs a “cold-shrink” process and solves the difficulty of mounting the cable into the cable connector sheath. However, the patent uses the outer shield layer as the stress control layer for the shielding end of the cable. For that reason, the outer shield layer must be designed into a tapered or flaring shape and, the manufacturing process is complicated and the waste product rate is high. Thus, although the above patent has to at least some degree solved the difficulty attendant with mounting the cable, it suffers from other defects.